KR20170136667A - AC electroluminescence device and finger scan sensor platform using the same - Google Patents

Abstract

The present invention relates to an alternating current (AC)-based light emitting device and a fingerprint recognition sensor platform using the same. According to an embodiment of the present invention, the AC-based light emitting device comprises: a lower electrode including first and second electrodes spaced apart from each other, and having AC power to be applied between the first and second electrodes; an electron injection layer disposed on the lower electrode; a light emitting layer disposed on the electron injection layer; a dielectric layer disposed on the light emitting layer; an upper electrode disposed on the dielectric layer, and including a first portion facing the first electrode and a second portion facing the second electrode; a first light emitting region defined by a first overlapping region of the light emitting layer between the first portion of the upper electrode and the first electrode of the lower electrode; and a second light emitting region defined by a second overlapping region of the light emitting layer between the second portion of the upper electrode and the second electrode of the lower electrode. Low production costs and a simple structure are secured.

Description

[0001] The present invention relates to an AC-based light emitting device and a fingerprint recognition sensor platform using the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC-based light emitting device, and more particularly, to an AC-based light emitting device with an inverted structure and a fingerprint sensor platform using the same.

The Future Human-centered Human Information System includes various information devices and systems for safety and convenience for individuals' social activities including health and security. In particular, sensing technology that efficiently detects human biological information and motion is an essential technology for human-machine interface. Organic materials, especially polymers based organic electronic devices, are known to be easy to apply to the human body due to their excellent mechanical flexibility. In addition, a highly sensitive organic electronic device based sensor for implementing a dormant-device interface technology is a device based on Organic Thin Film Transistors (OTFTs) and a device based on Organic Light Emitting Diodes (OLEDs) Is under development.

However, most conventional OLED sensors require a sensor film that is not a self-sensing device, but that is involved in actual sensing. Electro-luminescence (EL) emitted from OLEDs induces photoluminescence (PL) As a light source. In this case, the device structure is complicated, and manufacturing cost is increased due to the use of expensive sensing film.

Therefore, it may be necessary to develop a new principle and form of functional sensor to develop highly integrated device with low manufacturing cost and simple structure. In order to overcome this problem, it may be required to develop an AC-based light emitting device having a new driving principle and an operating mechanism.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an AC-based light emitting device having a new principle and shape for developing a highly integrated device having a low manufacturing cost and a simple structure.

Another object of the present invention is to provide a fingerprint sensor platform having the above-described advantages.

According to an exemplary embodiment of the present invention, an AC-based light emitting device includes a first electrode and a second electrode that are spaced apart from each other, and a first electrode and a second electrode, An electron injection layer disposed on the lower electrode, a light emitting layer disposed on the electron injection layer, a dielectric layer disposed on the light emitting layer, a first portion disposed on the dielectric layer and facing the first electrode, A first luminescent region defined by a first overlap region of the light emitting layer between the first portion of the upper electrode and the first electrode of the lower electrode and a second luminescent region defined by a first overlap region of the light emitting layer between the first portion of the upper electrode and the first electrode of the lower electrode, And a second light emitting region defined by a second overlapping region of the light emitting layer between the second portion of the upper electrode and the second electrode of the lower electrode The.

In one embodiment, the upper electrode is electrically connected between the first overlapping region of the first electrode and the second overlapping region of the second electrode with respect to the stacked structure of the lower electrode, the electron injection layer, the light emitting layer, . ≪ / RTI > During the first half period, an electric field is formed in the direction of the second electrode, the upper electrode and the first electrode of the lower electrode, and during the second half period, the first electrode of the lower electrode, An electric field may be formed in the direction of the electrode and the second electrode of the lower electrode.

In one embodiment, the light emission of the first light emitting region and the light emission of the second light emitting region may occur alternately. The first electrode may be formed of indium tin oxide (ITO), carbon nanotube (CNT), graphene, silver nano wire, metal mesh, or hybrid metal embedded Or may be a transparent electrode formed using one. The upper electrode may also be a conductive outer object.

In one embodiment, the electron injection layer may be formed of a material comprising a mixture of polyethyleneimine (PEI) and zinc oxide (ZnO-ZnO), Alq3 (tris (8-hydroxyquinoline) aluminum), Balq (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum Balq, Bebq2 bis (10- hydroxybenzo [h] quinolinato) -bearylum: Bebq2), BCP (2,9- diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), TPBI ((2,2 ', 2' '- benzene-1,3,5- phenyl-1H-benzimidazole), TAZ (3- (4-biphenyl) -4-phenyl-5-tert-butylphenyl- 1,2,4-triazole), NTAZ (4- (naphthalen- , 5-diphenyl-4H-1,2,4-triazole), NBphen (2,9-bis (naphthalen-2-yl) -4,7-diphenyl- 4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane: 3TPYMB), Phenyl-dipyrenylphosphine oxide, BP4mPy (3,3 ', 5,5'- 3-yl] biphenyl), TmPyPB (1,3,5-tri [3-pyridyl) -phen-3-yl] benzene), BmPyPhB (1,3- 3-yl) phenyl] benzene), Bepq2 (Bis (10-hydroxybenzo [h] quinolinato) ber (1,3,5-tri (p-pyrid-3-yl-phenyl) benzene), Bpy-OXD (1, 3-bis [2- (2,2'-bipyridine-6-yl) -1,3,4-oxadiazol-5-yl] benzene), BP-OXD-Bpy (6,6'- (4-Biphenyl-4-yl) -1,3,4-oxadiazol-2-yl] -2,2'-bipyridyl), tBu- 1,3,4-oxadiazole) and ADN (9,10-di (naphthalene-2-yl) anthracene).

According to another aspect of the present invention, an AC-based light emitting device may further include a hole injection layer disposed between the light emitting layer and the dielectric layer. The hole injection layer may be formed of at least one selected from the group consisting of PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate), phthalocyanine compound, DNTPD (N, N'- m-MTDATA (4,4 ', 4' '- tris (3-methylphenylphenylamino) triphenylamine), TDATA (4,4' 4 "-Tris (N, N-diphenylamino) triphenylamine), 2T-NATA (4,4'4" -tris { N'-bis (phenyl) -2,2'-dimethylbenzidine), PANI / DBSA (Polyaniline / Dodecylbenzenesulfonic acid), PANI / CSA (Polyaniline / Camphor sulfonicacid) , Poly (N-vinylcarbazole) (PVK), PANI / PSS (polyaniline) / poly (4-styrenesulfonate), N, N'- , poly (4-vinyltriphenylamine) (PVTTA), poly [N- (4- {N '- [4- , N'-bis (4-butylphenyl) -N, N'-bis (phenyl) benzidine (Poly-TPD).

According to another aspect of the present invention, an AC-based light emitting device includes a stacked structure including a lower electrode, an electron injection layer disposed over the lower electrode, a light emitting layer disposed over the electron injection layer, and a dielectric layer disposed over the light emitting layer. And a conductive outer object in close contact with the dielectric layer is electrically coupled to the light emitting layer through the dielectric layer to function as an upper electrode.

In one embodiment, the lower electrode includes a first electrode and a second electrode that are spaced apart from each other, and an AC power source may be applied between the first electrode and the second electrode. Alternatively, an AC power source may be applied between the lower electrode and the dielectric layer in the laminated structure. The conductive outer object may be one of a user's finger and a stylus pen. The light emitting layer may emit light in accordance with a touch input pattern input on the dielectric layer.

According to another aspect of the present invention, there is provided a fingerprint recognition sensor platform, comprising: an AC-based light emitting device having an alternating current structure; a light receiving sensor for detecting light through the AC- And performs a fingerprint recognition based on the light detected from the light source. The AC-based light emitting device having the inverted structure includes a first electrode and a second electrode that are spaced apart from each other, a lower electrode that is a transparent electrode to which an AC power is applied between the first electrode and the second electrode, A light emitting layer disposed on the electron injection layer, a dielectric layer disposed on the light emitting layer, a first portion disposed on the dielectric layer and facing the first electrode, and a second portion facing the first electrode, A first light emitting region defined by a first overlapping region of the light emitting layer between the first portion of the upper electrode and the first electrode of the lower electrode and a second light emitting region defined by the first electrode of the upper electrode, And a second light emitting region defined by a second overlap region of the light emitting layer between the second portion and the second electrode of the lower electrode.

In another embodiment, the upper electrode may be disposed between the first overlapping region of the first electrode and the second overlapping region of the second electrode with respect to the stacked structure of the lower electrode, the electron injection layer, the light emitting layer, And can be electrically coupled. During the first half period, an electric field is formed in the direction of the second electrode, the upper electrode and the first electrode of the lower electrode, and during the second half period, the first electrode of the lower electrode, An electric field may be formed in the direction of the electrode and the second electrode of the lower electrode. The light emission of the first light emitting region and the light emission of the second light emitting region may occur alternately.

According to an embodiment of the present invention, an alternating-current-based light emitting device having a reverse structure in which a dielectric layer is disposed between the upper electrode and the light emitting layer and an electron injection layer is disposed between the lower electrode and the light emitting layer, A highly integrated AC based light emitting device can be provided and an optimized light emitting mechanism is provided between the lower electrode and the light emitting layer so that the upper electrode can be used as various conductive materials.

According to another embodiment of the present invention, an object (e.g., a finger or a stylus pen) usable as a proximity touching means and having conductivity is used as an upper electrode of an AC-based light emitting element, An alternating current-based light emitting device having the above structure can be provided.

Further, according to another embodiment of the present invention, a fingerprint recognition sensor platform having the above-described advantages can be provided.

1A and 1B are a cross-sectional view and a perspective view of an alternating current-based light emitting device according to an embodiment of the present invention, respectively.
2A and 2B are a cross-sectional view and a perspective view of an alternating current-based light emitting device according to another embodiment of the present invention, respectively.
3A and 3B are energy band diagrams of an AC-based light emitting device according to an embodiment of the present invention.
4A and 4B are cross-sectional views illustrating an electric field flow of an AC-based light emitting device according to an embodiment of the present invention.
5A and 5B are graphs showing intensity of light of an AC-based light emitting device according to an embodiment of the present invention.
6A and 6B are views for explaining a configuration of a lower terminal of an AC-based light emitting device according to an embodiment of the present invention.
7 is a perspective view of an alternating current based light emitting device using various kinds of metal materials as upper electrodes according to another embodiment of the present invention.
8A is a graph illustrating the brightness of an AC-based light emitting device using various metal materials as an upper electrode according to an exemplary embodiment of the present invention.
8B is a graph showing luminance and current density of an AC-based light emitting device according to various metal materials according to a voltage change according to an embodiment of the present invention.
9 is a perspective view of an AC-based light emitting device using a touch input according to another embodiment of the present invention.
10 is a plan view of an alternating current-based light emitting device viewed from a lower electrode according to another embodiment of the present invention.
11 is a cross-sectional view of an AC-based light emitting device using a touch input according to another embodiment of the present invention.
12 is a perspective view of an alternating current based light emitting device using a touch input according to another embodiment of the present invention.
Figure 13 illustrates a fingerprint sensor platform in accordance with another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

Like numbers refer to like elements in the drawings. Also, as used herein, the term "and / or" includes any and all combinations of any of the listed items.

The terms used herein are used to illustrate the embodiments and are not intended to limit the scope of the invention. Also, although described in the singular, unless the context clearly indicates a singular form, the singular forms may include plural forms. Also, the terms "comprise" and / or "comprising" used herein should be interpreted as referring to the presence of stated shapes, numbers, steps, operations, elements, elements and / And does not exclude the presence or addition of other features, numbers, operations, elements, elements, and / or groups.

Reference herein to a layer formed "on" a substrate or other layer refers to a layer formed directly on top of the substrate or other layer, or may be formed on intermediate or intermediate layers formed on the substrate or other layer Layer. ≪ / RTI > It will also be appreciated by those skilled in the art that structures or shapes that are "adjacent" to other features may have portions that overlap or are disposed below the adjacent features.

As used herein, the terms "below," "above," "upper," "lower," "horizontal," or " May be used to describe the relationship of one constituent member, layer or regions with other constituent members, layers or regions, as shown in the Figures. It is to be understood that these terms encompass not only the directions indicated in the Figures but also the other directions of the devices.

In the present specification, the term " touch input pattern " defines a character input using a fingerprint of the finger of the touched user or a pen. In the present specification, the term " reverse structure " refers to a structure in which a dielectric layer is disposed below an upper electrode, not an upper portion of a lower electrode, and an electron injection layer for injecting electrons, And a structure in which a hole injection layer is disposed between the light emitting layer and the dielectric layer in order to improve light emission efficiency is defined as a 'reverse structure'. Also, in this specification, the term "transparent" is not to be construed as having transparency in the band of both visible light, infrared, or ultraviolet region, and should be interpreted as having transmittance in some wavelength bands of these regions.

In the following, embodiments of the present invention will be described with reference to cross-sectional views schematically illustrating ideal embodiments (and intermediate structures) of the present invention. In these figures, for example, the size and shape of the members may be exaggerated for convenience and clarity of explanation, and in actual implementation, variations of the illustrated shape may be expected. Accordingly, embodiments of the present invention should not be construed as limited to any particular shape of the regions shown herein. In addition, reference numerals of members in the drawings refer to the same members throughout the drawings.

1A and 1B are respectively a cross-sectional view and a perspective view of an alternating current-based light emitting device 100A according to an embodiment of the present invention.

1A, an AC-based light emitting device 100 includes a lower electrode 10 including a first electrode 11 and a second electrode 12, an electron injection layer 20, a light emitting layer 30, (50) and an upper electrode (60). The first electrode 11 and the second electrode 12 may be spaced apart from each other by an interval S1.

The first electrode 11 and the second electrode 12 of the lower electrode 10 may be transparent electrodes having high transmittance and conductivity. In one embodiment, at least one of the first electrode 11 and the second electrode 12 is formed of indium tin oxide (ITO), indium zinc oxide (IZO), carbon nanotube (CNT) But is not limited to, a transparent electrode including any one of carbon nanotube, carbon nanotube, graphene, silver nano wire, metal mesh, and hybrid metal embedded. In addition, the lower electrode 10 may be formed on a glass substrate (not shown) by a thin film deposition process such as sputter deposition or chemical vapor deposition.

AC power may be applied between the first electrode 11 and the second electrode 12 of the lower electrode 10. The first electrode 11 of the lower electrode 10 provides electrons to the electron injection layer 20 during a first half period during which a negative bias is applied to the first electrode 11, It is possible to provide holes to the electron injection layer 20 during the second half period in which a positive bias is applied to the one electrode 11. [ The second electrode 12 of the lower electrode 10 may also provide holes to the electron injection layer 20 during the first half cycle and electrons to the electron injection layer 20 during the second half cycle. The AC power source may be a sine wave or a square wave, but is not limited thereto.

The electron injection layer 20 may be disposed on the lower electrode 10 including the first electrode 11 and the second electrode 12. The electron injection layer 20 can transfer electrons to the light emitting layer 30 by controlling the movement of carriers (electrons and / or holes) supplied from the lower electrode 10. For example, the electron injection layer 20 transmits electrons supplied from the first electrode 11 of the lower electrode 10 during the first half period to the light emitting layer 30, and the first electrode 11 of the lower electrode 10 ) To the light emitting layer (30) during the second half cycle. The electron injection layer 20 blocks the holes supplied during the first half period from the second electrode 12 of the lower electrode 10 from being transferred to the light emitting layer 30, Electrons supplied during the second half period from the light emitting layer 12 to the light emitting layer 30. For this, the conduction band of the energy band of the electron injection layer 20 and the size of the base band can be designed to be low. In this case, the size of the energy barrier for injecting electrons from the first or second electrode 11, 12 to the electron injection layer 20 is reduced and the electron injection from the first or second electrode 11, The size of the energy barrier can be increased so that the injection of holes into the layer 20 is blocked. This will be described later in detail with reference to FIGS. 3A and 3B.

In one embodiment, the electron injection layer 20 may be formed of a mixture of polyethylenimine (PEI) and zinc oxide (ZnO) (ZnO: PEI), Alq3 (tris (8-hydroxyquinoline) aluminum) (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum Balq, Bebq2 bis (10- hydroxybenzo [h] quinolinato) -bearylum: Bebq2), BCP (2,9- diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), TPBI ((2,2 ', 2' '- benzene-1,3,5- phenyl-1H-benzimidazole), TAZ (3- (4-biphenyl) -4-phenyl-5-tert-butylphenyl- 1,2,4-triazole), NTAZ (4- (naphthalen- , 5-diphenyl-4H-1,2,4-triazole), NBphen (2,9-bis (naphthalen-2-yl) -4,7-diphenyl- 4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane: 3TPYMB), Phenyl-dipyrenylphosphine oxide, BP4mPy (3,3 ', 5,5'- 3-yl] biphenyl: BP4mPy), TmPyPB (1,3,5-tri [3-pyridyl) -phen-3-yl] benzene), BmPyPhB (1,3- pyridin-3-yl) phenyl] benzene), Bepq2 (Bis (10-hydroxybenzo [h] quinolinato) be pyryl-3-yl-phenyl) benzene: TpPyPB), Bpy- OXD (1,3-bis [2- (2,2'-bipyridine-6-yl) -1,3,4-oxadiazol-5-yl] benzene), BP-OXD- (Biphenyl-4-yl) -1,3,4-oxadiazol-2-yl] -2,2'-bipyridyl: BP-OXD-Bpy), tBu- 5- (4-tert-butylphenyl) -1,3,4-oxadiazole, and ADN (9,10-di (naphthalene-2-yl) anthracene). These materials are merely illustrative, and embodiments of the present invention are not limited thereto.

The light emitting layer 30 may be disposed on the electron injection layer 20. The light emitting layer 30 can emit light by electrons injected from the electron injection layer 20. For example, the electrons injected from the electron injection layer 20 can be accelerated by the electric field in the light emitting layer 30, collide with the emission atoms in the emission layer 30 by acceleration, State to the excited state, and the electrons of the emitting atoms are returned to the ground state in the excited state, so that light emission can be generated in the light emitting layer 30. [ In another embodiment, the electrons injected from the electron injecting layer 20 recombine with the holes of the base band of the light emitting layer 30, so that light emission can occur. 2A and 2B, when the hole injection layer 40 is disposed between the light emitting layer 30 and the dielectric layer 50, the hole injection layer 40 is formed in the light emitting layer 30 from the electron injection layer 20 Light emission may be caused by recombination of injected electrons and holes injected from the hole injection layer 40.

In one embodiment, the emissive layer 30 may have a polymeric matrix structure comprising a dye material. For example, a carbon nanotube may be combined with a dye material (e.g., PDY 132 (SY: super yellow) from Merck), and the carbon nanotube may be a single-walled nanotube (SWNT) ), Double-walled carbon nanotubes, and multi-walled nanotubes (MWNTs).

In various embodiments, the light emitting layer 30 may be either a host material as the organic material and a dopant material (or guest material) that is injected into the host material. The host material may include Alq3, CBP (4,4'-N, N'-dicarbazole-biphenyl), poly (n-vinylcarbazole) PVK, 9,10- 3-tert-butyl-9 (4,4 ', 4 "-tris (N-carbazolyl) -triphenylamine), TPBI (1,3,5-tris (N- phenylbenzimidazole- Di-2-naphthylanthracene), E3, distyrylarylene, BCzVB (1,4-bis [2- (3-Nethylcarbazolyl) vinyl] benzene), DPAVB (4- 4 '- [(di- p-tolylamino) styryl] stilbene) and NBDAVBi (N- (4 - ((E) -2- (6- (E) -4- (diphenylamino) styryl) naphthalene- ) vinyl) phenyl-N-phenylbenzenamine)), but it is not limited thereto. The dopant material may be selected from the group consisting of DCM (4-dicyanomethylene-2-methyl-6-pdimethylaminostyryl-4H-pyran), PtOEP, Ir (piq) 3, Btp2Ir (acac) ) 2 (acac), Ir (mpyp) 3, F 2 Irpic, (F 2 ppy) 2Ir (tmd), Ir (dfppz) 3, ter-fluorene, 4,4'-bis 4-diphenylaminostyryl) biphenyl , 5,8,11-tetra-t-butyl pherylene (TBPe), but is not limited thereto.

In another embodiment, the light-emitting layer 30 may be formed of an inorganic material such as ZnSe, ZnTe, CdS, CdSe, CaS, SrS, CaSe, SrSe, ZnMgS, CaSSe, CaSrS, CaGa2S4, SrGa2S4, BaGa2S4, CaAl2S4, SrAl2, BaAl2S4, Ga2O3 , Ca2O3, CaO, GeO2, SnO2, Zn2SiO4, Zn2GeO4, ZnGa2O4, CaGa2O4, CaGeO3, MgGeO3, Y4GeO8, Y2GeO5, Y2Ge2O7, Y2SiO5, BeGa2O4, Sr3Ga2O6, Zn2SiO4-Zn2GeO4, Ga2O3-Al2O3, CaO- But are not limited to, at least one material.

In another embodiment, the light emitting layer 30 may comprise a host material as an organic material and a dopant material implanted into the host material. Light can be emitted only by the host material or the dopant material. However, in order to improve the efficiency and brightness of light, the light emitting layer 30 may be formed by doping the host material with a dopant material. For example, a material having high quantum efficiency such as Quinacridone may be doped in Alq3, which is a host material having green luminescence, in order to increase the luminous efficiency.

A dielectric layer 50 may be disposed on the light emitting layer 30. [ The dielectric layer 50 may block the movement of carriers (i.e., electrons and / or holes) between the upper electrode 60 and the lower electrode 10. In one embodiment, the dielectric layer 50 may comprise silicon dioxide (SiO2), titanium monoxide (TiO2), tungsten dioxide (WO2), hafnium dioxide (HfO2), aluminum oxide ), Yttrium oxide or yttrium oxyd, cerium oxide (CeO2), Ta2O, zirconium dioxide, barium titanate (BaTiO3), SrTiO3 (STO), PVDF, P (VDF / And at least one of P (VDF / TrFE / HFP), P (VDF / TeFE), PVF, P (VF / TrFE), PAN, and P (VDCN / VAc) no.

An upper electrode 60 may be disposed on the dielectric layer 50. The upper electrode 60 includes a first portion 61 opposed to the first electrode 11 of the lower electrode 10 and a second portion 62 opposed to the second electrode 12 of the lower electrode 10 .

Since the carriers injected from the upper electrode 60 (i.e., electrons and / or holes) are blocked by the dielectric layer 50, the luminescent mechanism in the luminescent layer 30 may be substantially unaffected by the upper electrode 60 have. Accordingly, according to the embodiment of the present invention, the energy band structure between the upper electrode 60 and the underlying layers thereof does not affect the light emission mechanism, whereby a variety of conductive materials (e.g., Al, Au, Ag, Cu) or an object (e.g., a finger, a stylus pen) can be used as the upper electrode 60.

1A, the AC-based light emitting device 100A includes a light emitting layer 30A between the first portion 61 of the upper electrode 60 and the first electrode 11 of the lower electrode 10, Of the light emitting layer 30 between the second portion 62 of the upper electrode 60 and the second electrode 12 of the lower electrode 10 defined by the first overlap region of the light emitting layer 30 And a second light emitting area O2 defined by a second overlapping area. Line L1 is a virtual line for indicating the first overlapping region of the light emitting layer 30 between the first portion 61 of the upper electrode 60 and the first electrode 11 of the lower electrode 10, Line L2 is a virtual line for indicating the second overlapping region of the light emitting layer 30 between the second portion 62 of the upper electrode 60 and the second electrode 12 of the lower electrode 10. [

Although FIG. 1A shows two light emitting regions (the first light emitting region and the second light emitting region), the light emitting region may vary depending on the structure of the lower electrode 10. For example, if the lower electrode 10 is composed of a plurality of sub-electrodes, a plurality of sub-emission regions arranged corresponding to a plurality of sub-electrodes of the lower electrode 10 may be defined.

The first electrode 11 and the second electrode 12 of the lower electrode 10 spaced apart from the first electrode 11 and the second electrode 12 of the lower electrode 10 by an interval (70) may be applied. The upper electrode 60 can electrically couple the first overlapping region of the first electrode 11 of the lower electrode 10 and the second overlapping region of the second electrode 12 of the lower electrode 10. [ That is, the first electrode 11 and the second electrode 12 of the lower electrode 10 spaced apart from each other can be electrically coupled by the upper electrode 60.

The light emission occurs in the first light emitting region O1 during the first half period in the first overlap region O1 and the second overlap region O2 of the light emitting layer 30 electrically coupled by the upper electrode 60, And light emission may occur in the second overlap region 02 during the half period. Light emission occurs alternately in the first overlapping region and the second overlapping region. However, as the frequency of the AC power source is higher, the alternating light emitting time is shortened so that light emission appears simultaneously in the first overlapping region and the second overlapping region have.

2A and 2B are a cross-sectional view and a perspective view of an alternating current-based light emitting device 100B according to an embodiment of the present invention, respectively.

2A and 2B, the AC-based light emitting device 100B includes a lower electrode 10 including a first electrode 11 and a second electrode 12, an electron injection layer 20, an emission layer 30 A hole injection layer 40, a dielectric layer 50, and an upper electrode 60. There is no inconsistency with respect to the lower electrode 10 including the first electrode 11 and the second electrode 12, the electron injection layer 20, the light emitting layer 30, the dielectric layer 50 and the upper electrode 60 Reference may be had to the disclosure of Figures 1A and 1B.

The hole injecting layer 40 disposed between the light emitting layer 30 and the dielectric layer 50 can transfer holes to the light emitting layer 30. For example, since the hole injection layer 40 can not transfer electrons and / or holes from the upper electrode 60 to the light emitting layer 30 by the dielectric layer 50, holes are injected into the light emitting layer 30 to increase the efficiency of light emission. Lt; / RTI >

In one embodiment, the hole injection layer 40 may be formed of PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate), phthalocyanine compound, DNTPD m-MTDATA (4,4 ', 4' '- tris (3-methylphenylphenylamino) triphenylamine), bis- [4- (phenyl- (4,4'4 "-tris (N, - (2-naphthyl) -N-phenylamino} -triphenylamine) , N-N'-bis (phenyl) -2,2'-dimethylbenzidine, PANI / DBSA (Polyaniline / Dodecylbenzenesulfonic acid), PANI / CSA N-diphenyl-benzidine (NPB), poly (N, N'-diphenyl-benzylidene), polyaniline / camphor sulfonic acid, PANI / PSS phenylvinylcarbazole (PVK), poly (4-vinyltriphenylamine) (PVTTA), poly [N- (4- { PTPDMA) and poly [N, N'-bis (4-butylphenyl) -N, N'-bis But are not limited thereto.

When the hole injection layer 40 is disposed between the light emitting layer 30 and the dielectric layer 50, electrons injected from the electron injection layer 20 in the light emitting layer 30, The recombination probability of holes injected from the layer 40 can be increased. As a result, the probability of electrons having transition from the ground state to the excited state due to the recombination of electrons and holes is increased in addition to the electron impact, so that the AC light emission efficiency can be improved.

3A and 3B are energy band diagrams of an AC-based light emitting device according to an embodiment of the present invention.

3A, the lower electrode 10 is ITO, the electron injection layer 20 is ZnO / PEI, and the light emitting layer 30 is SY / MWNT. Referring to FIG. 5 shows an exemplary energy band diagram when the hole injection layer 40 uses PEDOT: PSS, the dielectric layer 50 uses SiO 2, and the upper electrode 60 uses Al (aluminum).

The work function of ITO is about -4.9 eV (201), the work function of Al is about -4.3 eV (202), the work function of PEDOT: PSS is about -5.2 eV (203) When the material of ZnO / PEI is used, the energy band of the electron injection layer 20 can be lowered from about -4.4 eV to about -7.1 eV (204) to about -4.1 eV to about -7.6 eV (205). When a material of SY / MWNT is used in the light emitting layer 30, the energy band may be about -3.0 eV to -4.95 eV (206).

In general, ITO injects holes, but in the embodiment of the present invention, an electron injecting layer 20 including a ZnO / PEI material may be introduced to provide an inverted structure for injecting electrons from ITO. This is because electrons injected from the ITO are easily transferred to the light emitting layer 30 through the electron injection layer 20 due to the low energy band structure of ZnO / PEI, while holes injected from the ITO are injected through the electron injection layer 20 The movement to the light emitting layer 30 can be blocked.

3A, when an electric field is formed from the upper electrode 60 to the lower electrode 10, that is, from the Al to the ITO direction during the first half period 210, electrons are injected from the ITO 220, Electrons from the ITO can easily move to the light emitting layer 30 (e.g., SY / MWNT) and collide with the atoms inside the light emitting layer 30 (230). Holes are injected into the light emitting layer 30 by the hole injection layer 40 although the holes from the Al are blocked by the high energy barrier of the dielectric layer 50. [ Accordingly, the light emitting layer 30 can emit light (230) by causing electrons to collide with each other or / and recombine electrons and holes to transition from the ground state to the excited state.

As shown in FIG. 3B, when an electric field is formed from the lower electrode 10 to the upper electrode 60, that is, in the direction from ITO to Al 250 during the second half period, holes are injected (201) Due to the energy barrier of layer 20, holes from the ITO may not be delivered to the light emitting layer 30 (e.g., SY / MWNT) (260). Also, electrons from Al can be blocked by the high energy band of the dielectric layer 50. In order for electrons to be injected into the light emitting layer 30 by the hole injecting layer 40, the work function of the hole injecting layer 40 should be smaller or larger than -3.0 eV, but -5.2 eV, ) (Eg, SY / MWNT) (270). Therefore, light emission may not be performed because collision between electrons or / and recombination of electrons and holes do not occur in the light emitting layer 30.

4A and 4B are cross-sectional views illustrating an electric field flow of an AC-based light emitting device according to an embodiment of the present invention.

Referring to FIG. 4A, power may be supplied to the first electrode 11 of the lower electrode 10 and positive power may be supplied to the second electrode 12 during a period t1. The first electrode 11 and the second electrode 12 of the lower electrode 10 spaced apart from each other are connected to the lower electrode 10, the electron injection layer 20, the light emitting layer 30, the hole injection layer 40, 50 and the upper electrodes 60 can be electrically coupled by the upper electrode 60 with respect to the laminated structure.

Here, the electric field is applied from the second electrode 12 to the upper electrode 60 of the lower electrode 10 to the first light emitting region 30 of the light emitting layer 30 in the second light emitting region 02 of the light emitting layer 30 O1) 302 and the upper electrode 60 to the first electrode 11 of the lower electrode 10 in the counterclockwise direction. 3A and 3B, light is emitted only in the first light emitting region O1 of the light emitting layer 30 by the energy band diagram.

Referring to FIG. 4B, (+) power is supplied to the first electrode 11 of the lower electrode 10 and (-) power is supplied to the second electrode 12 during a period of (t2). The first electrode 11 and the second electrode 12 of the lower electrode 10 spaced apart from each other may be electrically coupled to each other by the upper electrode 60.

Here, the electric field is applied from the first electrode 11 to the upper electrode 60 of the lower electrode 10 to the upper electrode 60, the second light emitting region 30 of the light emitting layer 30 from the first light emitting region 01 of the light emitting layer 30 O2) 312 and the upper electrode 60 to the second electrode 12 of the lower electrode 10 in the clockwise direction. Therefore, only the second light emitting region O2 of the light emitting layer 30 emits light by the energy band diagram of Figs. 3A and 3B.

5A and 5B are graphs showing intensity of light of an AC-based light emitting device according to an embodiment of the present invention.

Referring to FIG. 5A, there is shown a graph illustrating the intensity of an AC voltage signal according to a sinusoidal waveform. 1A and 1B, when a sine wave AC voltage signal of 1 kHz is applied between the first electrode 11 of the lower electrode 10 and the second electrode 12 of the lower electrode 10, 1 light emission occurs in the light emitting region and light emission may occur in the second light emitting region during the second half period.

Referring to FIG. 5B, there is shown a graph illustrating the intensity of light according to a voltage signal of a square wave. 1A and 1B, when a square wave voltage signal of 1 kHz is applied between the first electrode 11 of the lower electrode 10 and the second electrode 12 of the lower electrode 10, And light emission may occur in the second light emitting region during the second half period.

6A and 6B are views for explaining a configuration of a lower terminal of an AC-based light emitting device according to an embodiment of the present invention.

6A, the lower terminal constitutes a structure in which a plurality of sub-electrodes are arranged, and some sub-electrodes 11 of the plurality of sub-electrodes are connected to the (+) pole of the AC power source 70, And the remaining sub-electrodes 12 of the sub-electrodes may be connected to the (-) pole of the AC power source. The sub-electrode 11 and the sub-electrode 12 may be spaced apart from each other.

Referring to FIG. 6B, the lower terminal 10 may have a structure in which four sub-electrodes are arranged. A first AC power supply 70 is applied between the first sub-electrode 11 and the second sub-electrode 12 and a second AC power supply 70 'is applied between the third sub-electrode 13 and the fourth sub- Can be applied.

7 is a three-dimensional cross-sectional view of an alternating current based light emitting device using various kinds of metal materials as an upper electrode according to an embodiment of the present invention.

Referring to FIG. 7, the upper electrode 60 of FIG. 2A includes an AC-based light emitting device including four sub-electrodes 60a, 60b, 60c and 60d. Here, the material of the first sub-electrode 60a is Cu, the material of the second sub-electrode 60b is Ag, the material of the third sub-electrode 60c is Au, and the material of the fourth sub- Can be Al.

The electron injection layer 20, the light emitting layer 30, the hole injection layer 40, the dielectric layer 50, and the upper electrode 10 including the first electrode 11 and the second electrode 12 spaced apart from each other. The functions of the electrode 60 are the same as those of the lower electrode 10, the electron injection layer 20, the light emitting layer 30, the hole injection layer 40, the dielectric layer 50, and the upper electrode 60 ) May be referred to.

8A is a graph illustrating the luminance of an AC-based light emitting device using various metal materials as an upper electrode according to an exemplary embodiment of the present invention.

Referring to Figure 8a, SiO ₂ / Cu is the dielectric layer 50 in the light emitting device of the exchange based on FIG. 7 is SiO _2, and when the first sub-electrode (60a) of the upper electrode 60 is Cu, the upper electrode (60 ) the first sub-electrode (60a) and a lower electrode (10), and the luminance obtained by the overlapping area of the light-emitting layer 30 between, SiO ₂ / Au is a dielectric layer (50 in the light emitting device of the exchange based on FIG. 7) of the SiO ₂ And the second sub-electrode 60b of the upper electrode 60 is Ag, the luminance due to the overlapping region of the light-emitting layer 30 between the second sub-electrode 60b and the lower electrode 10 of the upper electrode 60 7, the dielectric layer 50 is SiO ₂ and the third sub-electrode 60c of the upper electrode 60 is Au, the SiO ₂ / Au of the third electrode 60 of the upper electrode 60, sub-electrode (60c) and a lower electrode (10), and the luminance obtained by the overlapping area of the light-emitting layer 30 between, and a SiO ₂ / Al is a dielectric layer (50) SiO ₂ on the light-emitting device of the exchange based on Figure 7 top electrode (60) 4 is that the light emission luminance due to the overlap area of sub-electrode fourth sub electrode (60d) and the lower electrode 10, the light-emitting layer 30 between the upper electrode 60 when (60d) is Al.

The luminance of SiO ₂ / Al, SiO ₂ / Au, SiO ₂ / Ag and SiO ₂ / Al is increased as the AC voltage increases and the luminance of each metal at some intervals (eg 65V to 100V) There are some differences. However, it can be seen that the light emission occurs irrespective of the material of the upper electrode 60 although the inter-metal luminance is slightly different. This ensures that the respective energy bands (see Figs. 3A and 3B) of the lower electrode 10, the electron injection layer 20, the light emission layer 30 and the hole injection layer 40 stacked below the upper electrode 60 are optimized The change of the luminance depending on the material of the upper electrode 60 is small because the movement of the carrier is blocked by the energy barrier of the dielectric layer 50 disposed under the upper electrode 60. [ Therefore, since the upper electrode 60 does not affect the luminance, any material having the conductivity of the material of the upper electrode 60 may be used.

8B is a graph showing luminance and current density of an AC-based light emitting device according to various metal materials according to a voltage change according to an embodiment of the present invention.

Referring to FIG. 8B, the luminance and the current density when a constant AC voltage is applied in the AC-based light emitting device of FIG. 6 are compared. The results show that there is a slight difference in the luminance of SiO2 / Al, SiO2 / Au, SiO2 / Ag and SiO2 / Al, but the current density of each metal hardly varies. Accordingly, the upper electrode 60 may be made of any material having conductivity, so that the upper electrode 60 may be replaced with a touch input of an object such as a user's finger as shown in FIG. 8A.

9 is a perspective view of an AC-based light emitting device using a touch input pattern according to another embodiment of the present invention.

Referring to FIG. 9, in the structure in which the remaining components except for the upper electrode 60 among the components of the AC-based light emitting device of FIG. 1A are laminated, a user's thumb ring 60e is touch input on the dielectric layer 50 . At this time, the fingerprint 801 of the touch input thumb finger 60e functions as the upper electrode 60 to emit light.

Since the fingerprint of the thumb input 60e touches the upper portion of the dielectric layer 50 substantially, the touch input pattern corresponding to the fingerprint 801 of the thumb 60e overlaps the light emitting layer 30 Light emission may occur in the region. Thus, the light emission can be displayed in the form of a fingerprint of the thumb 60e. In addition, since the lower electrode 10 is a transparent electrode, the finger 803 of the finger 60e of the thumb 60e can be transmitted through the lower electrode 10, as shown in FIG. 10 is a plan view of an alternating current-based light emitting device viewed from the lower electrode 10 according to another embodiment of the present invention.

11 is a cross-sectional view of an AC-based light emitting device using a touch input according to another embodiment of the present invention.

Referring to FIG. 11, in the structure in which the remaining components other than the upper electrode 60 among the components of the AC-based light emitting device of FIG. 2A are stacked, a user's thumb 60e is touched on the dielectric layer 50 The touch input thumb 60e functions as the upper electrode 60 to emit light.

However, there is a difference between the connection of applying the AC-based light emitting element of FIG. 9 and the AC power supply. 9, an AC power source 70 is applied between the first electrode 11 and the second electrode 12 of the lower electrode 10. In FIG. 11, an AC power source 70 is provided between the dielectric layer 50 and the lower electrode 10, (70) may be applied. In FIG. 11, the first electrode 11 and the second electrode 12 may be formed of one electrode without being spaced apart from each other in the lower electrode 10.

12 is a perspective view of an alternating current based light emitting device using a touch input according to another embodiment of the present invention.

Referring to FIG. 12, a character corresponding to the touch input pattern can be displayed using a conductive pen 60f such as a stylus pen. For example, if a touch input pattern corresponding to the 'NPL' character is provided on the dielectric layer 50 by the stylus pen 60f instead of the finger in FIG. 8A, then the light corresponding to the 'NPL' character in the alternating- .

Although the embodiments described above mainly disclose an alternate current based light emitting device, this is merely exemplary, and those skilled in the art will appreciate that elements used in a fingerprint sensor platform, such as the one shown in FIG. 11, It will be understood that the present invention can be applied.

The sensor platform means an independent device composed of an AC-based light emitting device and a photodiode.

Figure 13 illustrates a fingerprint sensor platform 200 in accordance with another embodiment of the present invention.

Referring to FIG. 13, the fingerprint recognition sensor platform 200 may include an AC-based light emitting device 100, a light receiving sensor layer 210, and a processor 220. As far as the ac-based light emitting device 100 is concerned, reference may be had to those disclosed in Figs. 1A and / or 2A.

The light receiving sensor layer 210 is disposed on the second main surface P1 opposite to the first main surface of the lower electrode 10 on which the electron injection layer 20 of the AC based light emitting device 100 is formed, The light emission from the first light emitting region O1 or the second light emitting region 02 of the light emitting layer 30 can be detected. A photodiode may be used as the light receiving sensor, but the present invention is not limited thereto. For example, the photodiode may be a phototransistor, a port transistor, a photothyristor, a photomultiplier tube, a photodiode using photoconductivity of cadmium sulfide (CdS), a charge coupled device (CCD) oxide semiconductor image sensor, or may be combined with any one of them to form a light receiving sensor. The array of the light receiving sensors may be any one of or a combination of CCD type, MOS type, CID (charge injection device) type, PDC (plasma coupled device) type, CPD (charge priming device) type and BBD have.

The processor 220 may analyze the light emission detected by the light receiving sensor layer 210 to perform fingerprint recognition. For example, the processor 220 may generate an image based on a signal detected from the light receiving sensor layer 210 as an input pattern in contact with or in close contact with the dielectric layer 50 of the AC-based light emitting device 100, Can be displayed on a display (not shown). The contacted or closely contacted shape may be, but is not limited to, a fingerprint of a touch input finger or at least one character input via a conductive pen.

In various embodiments, the light-receiving sensor layer 210 and / or the processor 220 in the fingerprint sensor platform 200 may be replaced by separate electronic devices. For example, the light transmitted through the lower electrode 10 of the AC-based light emitting devices 100A and 100B can be photographed through the image sensor of the smart phone, and a fingerprint recognition app or application installed in the smart phone can be used.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be clear to those who have knowledge.

100: AC-based light emitting device
10: Lower electrode
20: electron injection layer
30: light emitting layer
40: Hole injection layer
50: dielectric layer
60, 60a, 60b, 60c, 60d, 60e, 60f:
210: light receiving sensor layer

Claims (19)

A lower electrode including a first electrode and a second electrode spaced apart from each other and to which an AC power is applied between the first electrode and the second electrode;
An electron injection layer disposed on the lower electrode;
A light emitting layer disposed on the electron injection layer;
A dielectric layer disposed on the light emitting layer;
An upper electrode disposed on the dielectric layer, the upper electrode including a first portion facing the first electrode and a second portion facing the second electrode;
A first light emitting region defined by a first overlapping region of the light emitting layer between the first portion of the upper electrode and the first electrode of the lower electrode; And
And a second light emitting region defined by a second overlapping region of the light emitting layer between the second portion of the upper electrode and the second electrode of the lower electrode. The method according to claim 1,
The upper electrode electrically couples the first overlap region of the first electrode and the second overlap region of the second electrode with respect to the structure in which the lower electrode, the electron injection layer, the light emitting layer, and the dielectric are stacked Characterized by an alternating current based light emitting element. The method according to claim 1,
An electric field is formed in the direction of the second electrode, the upper electrode, and the first electrode of the lower electrode of the lower electrode during a first half period,
Wherein an electric field is formed in a direction of the first electrode, the upper electrode, and the second electrode of the lower electrode during a second half period. The method according to claim 1,
Wherein the light emission of the first light emitting region and the light emission of the second light emitting region occur alternately. The method according to claim 1,
The first electrode may be formed of indium tin oxide (ITO), carbon nanotube (CNT), graphene, silver nano wire, metal mesh, or hybrid metal embedded An AC-based light emitting device, which is a transparent electrode formed using one. The method according to claim 1,
The electron injecting layer may be formed of a material comprising a mixture of polyethyleneimine and zinc oxide (ZnO-PEI), Alq3 (tris (8-hydroxyquinoline) aluminum), Balq (Bis -8-quinolinolate) -4- (phenylphenolato) aluminum Balq, Bebq2 bis (10-hydroxybenzo [h] quinolinato) -bearylum Bebq2, BCP (2,9- 10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), TPBI ((2,2 ', 2''- benzene-1,3,5-triyl) -benzimidazole), TAZ (3- (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4- (naphthalen- -4H-1,2,4-triazole), NBphen (2,9-bis (naphthalen-2-yl) -4,7-diphenyl- pyridine-3-yl) phenyl) borane: 3TPYMB), Phenyl-dipyrenylphosphine oxide, BP4mPy (3,3 ', 5,5'-tetra [ yl] biphenyl), TmPyPB (1,3,5-tri [(3-pyridyl) -phen-3-yl] benzene), BmPyPhB (1,3- phenyl] benzene), Bepq2 (Bis (10-hydroxybenzo [h] quinolinato) beryllium), DPPS 3-yl) phenyl) silane), TpPyPB (1,3,5-tri (p-pyrid-3-yl-phenyl) benzene), Bpy-OXD - (2,2'-bipyridine-6-yl) -1,3,4-oxadiazol-5-yl] benzene), BP-OXD-Bpy (6,6'-bis [5- (biphenyl- ) -1,3,4-oxadiazol-2-yl] -2,2'-bipyridyl), tBu-PBD (2- (4-Biphenylyl) -5- (4- -oxadiazole) and ADN (9,10-di (naphthalene-2-yl) anthracene). The method according to claim 1,
And a hole injection layer disposed between the light emitting layer and the dielectric layer. 8. The method of claim 7,
The hole injection layer may be formed of at least one selected from the group consisting of PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate), phthalocyanine compound, DNTPD (N, N'- m-MTDATA (4,4 ', 4''- tris (3-methylphenylphenylamino) triphenylamine), TDATA (4,4' 4 "-Tris (N, N-diphenylamino) triphenylamine), 2T-NATA (4,4'4" -tris { N'-bis (phenyl) -2,2'-dimethylbenzidine), PANI / DBSA (Polyaniline / Dodecylbenzenesulfonic acid), PANI / CSA (Polyaniline / Camphor sulfonicacid) , Poly (N-vinylcarbazole) (PVK), PANI / PSS (polyaniline) / poly (4-styrenesulfonate), N, N'- , poly (4-vinyltriphenylamine) (PVTTA), poly [N- (4- {N '- [4- Based light emission comprising at least one material selected from the group consisting of N'-bis (4-butylphenyl) -N, N'-bis (phenyl) Here. The method according to claim 1,
Wherein the upper electrode is a conductive outer object. A lower electrode;
An electron injection layer disposed on the lower electrode;
A light emitting layer disposed on the electron injection layer; And
And a dielectric layer disposed above the light emitting layer,
And a conductive outer object in close proximity to said dielectric layer is electrically coupled to said light emitting layer through said dielectric layer to function as an upper electrode. 11. The method of claim 10,
Wherein the lower electrode includes a first electrode and a second electrode that are spaced apart from each other, and an AC power source is applied between the first electrode and the second electrode. 11. The method of claim 10,
Wherein an AC power source is applied between the lower electrode and the dielectric layer in the laminated structure. 11. The method of claim 10,
Wherein the conductive outer object is one of a user's finger and a stylus pen. 11. The method of claim 10,
Wherein the light emitting layer emits light according to a touch input pattern input on the dielectric layer. An alternating current based light emitting device having a reverse structure;
A light receiving sensor for detecting light through the ac-based light emitting device having the inverted structure; And
And a processor for performing fingerprint recognition based on the light detected by the light receiving sensor. 16. The method of claim 15,
In the ac-based light emitting device having the reverse structure,
A lower electrode including a first electrode and a second electrode spaced apart from each other and to which an AC power is applied between the first electrode and the second electrode;
An electron injection layer disposed on the lower electrode layer;
A light emitting layer disposed on the electron injection layer;
A dielectric layer disposed on the light emitting layer;
An upper electrode disposed on the dielectric layer, the upper electrode including a first portion facing the first electrode and a second portion facing the second electrode;
A first light emitting region defined by a first overlapping region of the light emitting layer between the first portion of the upper electrode and the first electrode of the lower electrode; And
And a second light emitting region defined by a second overlapping region of the light emitting layer between the second portion of the upper electrode and the second electrode of the lower electrode. 17. The method of claim 16,
The upper electrode electrically couples the first overlap region of the first electrode and the second overlap region of the second electrode with respect to the structure in which the lower electrode, the electron injection layer, the light emitting layer, and the dielectric are stacked Fingerprint recognition sensor platform that features. 17. The method of claim 16,
An electric field is formed in the direction of the second electrode, the upper electrode, and the first electrode of the lower electrode of the lower electrode during a first half period,
And an electric field is formed in the direction of the first electrode, the upper electrode, and the second electrode of the lower electrode during the second half period. 17. The method of claim 16,
Wherein light emission of the first light emitting region and light emission of the second light emitting region occur alternately.

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